Mod6

Introduction toResearch Methods& Experimental Design : Introduction to Research Methods andamp; Experimental Design Module 6


Objectives : Objectives Students will be able to: list the steps involved in the research process. identify societal goals and purposes for research. develop research objectives from goals. use established criteria to assess research hypotheses. categorize research variables create operational definitions define samples and explain sampling methods. determine the difference between reliability and validity. evaluate the importance of replication and randomization. explain experimental, causal-comparative, correlational, and descriptive research methods. identify Green’s ten principles of research design.


Conducting research : Conducting research


Research process : Research process Society’s goals and purposes Problems identified Objectives identified andamp; refined Question(s) isolated Hypothesis or Research Question developed Research andamp; sampling design Data collection Data managed andamp; analyzed Results interpreted Presentation of results


Society’s goals and purposes : Research begins with a goal and a purpose Public and agency interests in water resources are grounded in their values and missions. Based on their perspectives, the public and agencies identify problems. The problems lead to more specific questions that form the starting point for research. . Society’s goals and purposes


Society’s goals and purposes : What types of goals and uses might people have for their lakes, rivers, streams, and reservoirs? Society’s goals and purposes


Society’s goals and purposes : Society’s goals generally address: Water quantity Water quality Impacts of water use Water resource protection or remediation Improved understanding of the resource Responding to a resource crisis Society’s goals and purposes


Society’s goals and purposes : Water quality Aquatic Life andamp; Wildlife Support Fish/Shellfish Consumption Drinking Water Supply Recreation Agriculture Society’s goals and purposes


From goals to objectives : Social Goal Problem Objective From goals to objectives


From goals to objectives : From goals to objectives


From goal, to problem, to objective, to question, to a hypothesis : From goal, to problem, to objective, to question, to a hypothesis Goal: Society wants to reduce eutrophication in Halsted’s Bay, in Minnetonka, MN. Problem: It’s not known if the nutrients causing eutrophication come from the sediments or non-point sources. Objective: Determine the probable source of the nutrients causing eutrophication. Question: Are sediment nutrients affecting eutrophication? Refined Q: Are sediment nutrients re-suspended in the Bay? Final Hypothesis: Sediments in Halsted’s Bay are not re-suspended after major wind events.


Hypothesis : Hypothesis Declarative statements Testable Are resolved mathematically Address independent and dependent variable(s)


Hypothesis: Which statements are declarative? : Hypothesis: Which statements are declarative? Turbidity decreases fish reproduction. Does increased phosphorous in the water lead to algae blooms? How does water temperature affect development of invertebrates? Find the impacts of erosion on a stream. Study the spread of aquatic invasive species. Feedlot runoff does not affect the oxygen levels in Whatchagot River. How do two-cycle outboards affect the water quality of Lake Whereisit? Identify the source of pollution affecting the river. How is mercury entering our northern lakes?


Hypothesis: Which are testable? : Hypothesis: Which are testable? Aquatic invasive species can be spread by recreational boats. Macrophytes are beneficial. Development causes erosion. Fertilizers cause water pollution. Eliminating the introduction of oil and gasoline into stormwater drains will improve lake water quality according to the US EPA Clean Water Act.


Hypothesis : Example Hypothesis: Sediments in Halsted’s Bay are not re-suspended after major wind events. Hypothesis


Variables : Variables Variable: Any thing or event that can change (have more than one value) while still having the same identity. What stream variables might affect the number and type of fish caught in this electro-shocking effort?


Variables : Variables can be: Discrete Continuous Nominal Ordinal Variables


Variables : Categorize these variables: Water depth Sex of an organism Dissolved oxygen Turbidity Stream flow Dates for spawning Water color Growth rates pH Electrical conductivity Dominance Where something occurs (spatial variable) When something occurs (temporal variable) Variables


Variables: Independent and dependent : Variables: Independent and dependent What is the independent/dependent variable? Increases in turbidity result in decreased dissolved oxygen Increasing algae populations result in increased dissolved oxygen. Stream flow rates correlate to electrical conductivity. Water temperature affects the start of spawning for trout. The presence of PCB’s affects the reproductive success of sturgeon.


Operational definitions : Operational definitions Specifically defining a variable as a type of data in a way that permits another researcher to measure the same variable.


Operational definitions : Operational definitions Create operational definitions for these phrases 'large' lake 'narrow' river 'young' fish 'rocky' bottom 'fast-moving' stream 'clean' water 'early' spawning 'cold' water


Review : Review Improve these hypotheses: Carp populations affect water quality. Shoreline vegetation is important for fish in a stream. Development should not occur on stream banks with high slopes. New reservoirs have more macro-invertebrates. Decreasing nutrient inputs into a lake improves water quality.


Review process of hypothesis development : Review process of hypothesis development Society’s goals andamp; purposes Problems identified Objectives identified andamp; refined Question(s) isolated Hypothesis or Research Question developed Research andamp; sampling design Data collection Data managed andamp; analyzed Results interpreted Presentation of results


Review process of hypothesis development : Review process of hypothesis development Society’s goals andamp; purposes Problems identified Objectives identified andamp; refined Question(s) isolated Hypothesis or Research Question developed Research andamp; sampling design Data collection Data managed andamp; analyzed Results interpreted Presentation of results


Research and sampling design : Research and sampling design Who collects what, when, where, and how?


Research and sampling design : Research and sampling design Basic concepts and principles Variable Operational definition Sample Variability Replication Independence Basic concepts and principles Sample size Uncertainty Randomization Control Reliability Validity


Research and sampling design : http://www.pnl.gov/breakthroughs/images/fall02/fish.jpg Sample: A representative portion of the population. The size of the sample is referred to as 'n'. The entire population is referred to as 'N'. Research and sampling design


Research and sampling design : Research and sampling design Types of sampling Convenience or accidental sampling Random sampling Stratified random sampling Cluster sampling Systematic sampling


Sample types : Sample types Which type of sampling might you use… If you were looking for population information about a species like walleye? If you wanted to show the impacts of a pollutant on benthic macro-invertebrates in a stream? If you wanted to determine the impacts of road salt on electrical conductivity in streams? If you wanted to determine water clarity in a lake?


Variability : Sources Individual differences (sampling error) Measurement error Variability


Validity : Validity Do the methods and tools truly measure what they are intended to measure? Internal External Statistical


Reliability : Reliability Do the methods and tools/instruments produce consistent results across multiple observations?


Research horror stories : Research horror stories Determining life history of a benthic amphipod


Research horror stories : Research horror stories Studying animals that live between sand grains on a beach


Treatment : Treatment Refers to the variable that is manipulated and/or being investigated as the predictor/causative variable: the independent variable.


Treatment : Treatment What’s the treatment? Temperature is being investigated for its effects on fish growth rates. Water clarity is being studied to see if it will improve if phosphorous inputs to the lake are reduced. Different levels of photosynthetic activity are being studied to see their effects on DO.


Research horror stories : Research horror stories


Replication : Replication Replicate samples: Multiple samples or observations are desirable and increase confidence in research conclusions and predictions. Affects reliability Consider time, space, scale, and samples in designing replications.


Replication : Replication Direct replication Systematic replication


Randomization : Randomization Sampling Spatial Temporal Treatment Spatial Temporal


Layout in research design : Layout in research design Sample size Randomization Replication


Research horror stories : Research horror stories


Research and sampling design basics : Research and sampling design basics Control variables Collect replicate sample data Collect sample data randomly Collect enough sample data for analysis Conduct preliminary sampling to test the research/sampling design Test and consider limitations of sampling methods and techniques


Categories of scientific research : Categories of scientific research Experimental Causal-comparative Correlational Descriptive


Experimental research : Experimental research Identifies cause-effect relationships Involves the manipulation of independent variables in the process of testing a hypothesis Attempts to constrain other variables Results in statistical probability statement Most laboratory research is experimental Some field research is experimental


Experimental research design : Experimental research design


Experimental research : Experimental research Limitations May leave out important variables from consideration May be 'artificial' Often restricted in small scales of time, space, and limited range of treatment conditions May be ethically inappropriate


Causal-comparative research : Causal-comparative research Draws from two groups that are different on a critical variable (the independent variable) Subjects are not randomly assigned (instead they belong to categorical groups) Uses dependent and independent variables, but independent is varied by selecting the situation, not deliberately varied


Causal-comparative research : Causal-comparative research


Causal-comparative research : Causal-comparative research Limitations Non-treatment variables cannot all be kept equal Often temporal and/or spatial scales are used in layout design


Correlational research : Correlational research Finds relationships among variables Does not define cause-effect Does not attempt to determine effects of independent variable


Correlational research : Correlational research


Correlational or simple experimental research : Example: Collect electrical conductivity data in streams before and after rainfalls. Correlational or simple experimental research


Descriptive/naturalistic research : Descriptive/naturalistic research Describes a situation Does not manipulate variables Does not attempt to define cause-effect relationship


Descriptive research : Example: Collect walleye egg hatching data below pulp mill outfall. Descriptive research


Applied water resources research : Applied water resources research Inventory/census Surveillance Monitoring


Monitoring : Monitoring Compliance Hypothesis testing Trend Retrospective (effects-oriented) Predictive (stressor-oriented) Anticipatory


Compliance monitoring : Compliance monitoring


Hypothesis testing monitoring : Hypothesis testing monitoring


Trend monitoring : Trend monitoring


Retrospective (effects) oriented monitoring : Retrospective (effects) oriented monitoring


Predictive (stressor-oriented) monitoring : Predictive (stressor-oriented) monitoring


Anticipatory monitoring : Anticipatory monitoring


Recommendations for field studies: : Recommendations for field studies: Conduct long-term studies whenever possible Conduct experiments AND observations at several spatial scales Use tractable organisms and systems to establish processes Use natural replicates whenever possible Be conscious of repeatability Embrace, do not shun, natural variation!


Green’s ten principles : Green’s ten principles Be able to state your research question concisely. Take replicate samples. Use an equal number of randomly allocated replicate samples for each combination of controlled variables. Use a control. Carry out some preliminary sampling to provide a basis for evaluation of sampling design and statistical analysis options. Verify that your sampling device or method is appropriate. If you are sampling a large area, define appropriate sub-areas and use proportional sampling. Use replicate samples to get the precision desired. Test your data for error variation. Stick with the results of your statistical analysis.


Module review : Module review Goal Objective Problem Hypothesis Inventory Retrospective monitoring Predictive monitoring Anticipatory monitoring Applied research Basic research Control Variable (types?) Descriptive research Correlational research Experimental research Replication Reliability Validity Randomization


References : References Green, R. 1979. Sampling Design and Statistical Methods for Environmental Biologists. John Wiley andamp; Sons, New York. North American Lake Management Society and Terrene Institute. 2001. Managing Lakes and Reservoirs. North American Lake Management Society, Madison, WI. Patten, M. 2000. Proposing Empirical Research: A Guide to the Fundamentals. Pryczak Publishing: Los Angeles, CA. Perry, J. and Vanderklein, E. 1996. Water Quality: Management of a Natural Resource. Blackwell Science, Inc., Cambridge, MA. Quinn, G. andamp; Keough, M. 2002. Experimental Design and Data Analysis for Biologists. Cambridge University Press: New York, NY. Excellent intro abt scientific process! Resetarits, W. andamp; Bernardo, J. (Eds) (1998). Experimental Ecology: Issues and Perspectives. Oxford University Press: New York, NY. Spellerberg, I. 1993. Monitoring Ecological Change. Cambridge University Press: New York, NY. Good intro to value of monitoring and types of monitoring. Valiela, I. 2001. Doing science: Design, Analysis, and Communication of Scientific Research. Oxford University Press: Oxford, England. http://www.lbl.gov/Education/ELSI/research-main.html 1/6/03 http://people.clemson.edu/~alanj/Lec1-history.ppt 1/6/03